Research Data Analyser

Statistical Analysis Platform for Medical Research


Dataset Overview

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Variable Summary

Deep scan of data structure, missingness, and format errors.


Observations
Variables
Missing Cells
Duplicate Rows

'Content' shows Mean (SD) for numeric variables, or Top Category (%) for factors.

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Variable Management & Modification




Hold Ctrl/Cmd to select multiple


Current Filters Applied:

Data Preview

Before (Counts)
After (Preview)

Use descriptive names. Avoid spaces (use underscores instead).

Preview (First 10 rows)


                        

Manage missing values (NA). You can use simple imputation (mean/mode) or advanced AI-based imputation (MICE).

Switch to 'mice' package to handle complex missing data patterns.

Pre-Imputation Status

Note: Standard methods update one variable at a time.
MICE Mode: Advanced imputation using chained equations.
Only these columns will be modified.

Variables used to learn the patterns (leave empty for All).

Workflow Guide
  • Targets: The columns that have missing values you want to fix.
  • Predictors: Columns that provide information. MICE uses correlations in predictors to guess the targets.

Example: Use 'Age' and 'Weight' (Predictors) to fill in missing 'Height' (Target).

Hold Ctrl/Cmd to select multiple.
Deletion Condition

Delete row if missing count is:


When to use this tab: If any regression assumption check shows FAIL , use the tools below to transform or clean your variables, then re-run the regression with the corrected variable(s).

Create a new transformed variable from an existing one. Use for: Linearity, Normality, Homoscedasticity, Log-linearity (Cox/Binary) FAIL.



Delete a variable that causes multicollinearity. Use for: Multicollinearity (VIF) FAIL.

Deletion is permanent for this session. Use Reset to Original in Dataset Overview to undo.
Hold Ctrl/Cmd to select multiple.


Exclude rows with extreme values on a selected variable. Use for: Influential Outliers FAIL.




Merge small or sparse categories into one group. Use for: Complete Separation (Binary regression) FAIL.



Propensity Score Matching

Binary exposure/treatment variable
Variables to balance between treatment groups
Nearest is most common
Controls per treated case
Maximum propensity score difference



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Covariate Balance Assessment
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Download Modified Dataset

Export the current working dataset with all modifications applied.



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Visual Exploration

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Cutpoint Analysis Tool

Step 1: Variable Selection
Variable you want to explore for dichotomisation
Binary or Survival outcome


Duration until event
Event indicator (0/1) should be the outcome variable selected above

Analysis Summary


Method: ROC Curve Analysis

Approach: Finds cutpoint that maximizes Youden Index (Sensitivity + Specificity - 1)

Best for: Binary outcomes, balanced prediction, diagnostic tests

Requires: Binary outcome variable (0/1 or Yes/No)


Optimal Cutpoint Results
ROC Curve
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Distribution with ROC Cutpoint
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Method: Maximally Selected Rank Statistics

Approach: Tests all possible cutpoints, selects one with maximum statistical difference

Best for: Survival data, exploratory analysis, hypothesis generation

Warning: High overfitting risk - always validate externally!


MaxStat Cutpoint Results
Kaplan-Meier Survival Curves
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Outcome Distribution by Groups
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Distribution with MaxStat Cutpoint
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Method: LOWESS Smoothing

Approach: Locally weighted scatterplot smoothing to visualise relationship

Best for: Exploring non-linearity, identifying natural breakpoints

Use: Understand relationship pattern before dichotomising


Plot Settings
Lower = flexible; Higher = smoother

LOWESS Smooth Curve
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Pattern Interpretation

Derivative Analysis: Rate of Change
Shows where the relationship changes most rapidly. Peaks indicate potential natural cutpoints.
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Comparing Methods

Different methods may suggest different cutpoints. Consider:

  • Agreement: If ROC and MaxStat agree (±2 units), cutpoint is robust
  • LOWESS pattern: If linear, any cutpoint is arbitrary; if clear breakpoint, use it
  • Clinical guidelines: Always prioritise established clinical cutpoints
  • External validation: Data-driven cutpoints must be validated in independent dataset
Cutpoint Comparison Table
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Visual Comparison
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Inferential Statistics Calculator

Enter summary statistics manually to compute confidence intervals and perform inferential test.

Proportions (Categorical Data)
Group 1

Group 2


Means (Continuous Data)
Group 1

Group 2

Mann-Whitney requires the median and IQR, not the mean and SD. Enter median as 'Mean' and IQR as 'SD' for an approximate test.


Quick Reference: Chi-square is used when all expected cell counts ≥ 5; Fisher exact is used when any cell < 5 (auto mode selects this automatically). For means, use Welch t-test by default unless equal variance has been confirmed (e.g., via Levene's test). Wilson CI for proportions is preferred over normal approximation for small n or extreme proportions.

Correlation Analysis


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Multiple Correlation Matrix




Download Matrix (.csv)
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Correlation Coefficients & P-values
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Linear Regression Analysis

Model Refinement

Automatically selects optimal variables using bidirectional AIC selection.
Assess multicollinearity among predictors (VIF > 5 indicates concern).

Select numeric or categorical variables as predictors


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Model Diagnostics
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Sensitivity Analysis — Influential Observations (Linear Regression)

Assesses whether the main results change materially after removing observations whose Cook's distance exceeds the threshold (default 4/n). A robust model shows negligible change in estimates after exclusion.

Settings

Download CSV Download HTML

Repeated Measures Analysis (Linear Mixed Effects)

Analyse longitudinal data. First, define your data structure below, then choose to build a model or a graph.
1. Define Data Structure

Model Specification


Regression Results
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Longitudinal Visualization
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Step 1: Analysis Settings

Use if you have small sample sizes or '0' events in a group (Separation). Stepwise selection is disabled for Firth.

Model Refinement

Automatically selects the best variables using Backward/Forward AIC selection.
Click to check for multicollinearity before running the final model.

Step 2: Model Variables

Variables selected here will be included in the Multivariable columns.



Core Variables

Select numeric time variable

Kaplan-Meier Survival Analysis

Variable to stratify survival curves

Comma-separated time points

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Cox Regression Analysis

Model Refinement

Automatically selects optimal predictors using bidirectional AIC selection.
Assess multicollinearity among covariates (VIF > 5 indicates concern).
Select variables for univariable and multivariable Cox regression


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Sensitivity Analysis — Influential Observations (Cox Regression)

Identifies poorly-fitted or influential observations using either deviance residuals (|d| > threshold, default 3) or Cook's distance (> 4/n). The model is re-run after exclusion and estimates are compared side-by-side.

Settings

Download CSV Download HTML

1. Score Development & Weighting

Select variables to include in the score
Variable Weighting Analysis
View coefficients to determine appropriate weights.

Logistic Regression Results (Basis for Weighting):
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Assign Weights

Score Created! You can now use this variable in the ROC Analysis below.

2. Clinical Risk Calculator (Simulation)

Patient Inputs


3. ROC Analysis

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Performance

Optimal Cutoff (Youden)

4. Save & Download Data

Download the dataset including the newly created score variable.

5. Diagnostic Evaluation Tools

Diagnostic Accuracy Calculator
Enter values from a 2x2 contingency table.


Likelihood Ratio Calculator
Calculate post-test probability.



Analysis Configuration


Clinical Scale Mode
Enter the maximum score for EACH question/item (e.g., 5 for 0-5 scale, 4 for 0-4 scale). Total maximum will be calculated automatically.

Item Selection
Select 3+ numeric items for analysis.
Item Reversal
Reverse scoring: (max + min) - original_score. E.g., 5-point scale: 5→1, 4→2, 3→3.

Advanced Settings



1. Reliability & Internal Consistency


2. Overall Statistics & Score Distribution


Score Distribution
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3. Item Health Check


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4. Validity & Structural Analysis


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Kaiser-Meyer-Olkin (KMO) and Bartlett's Test assess whether your data is suitable for factor analysis.


Item Response Theory (IRT) curves showing the probability of correct response by ability level.

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Results

Power Analysis Curve

Visualisation of how sample size affects statistical power

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